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A. J. KESCHEH. S'YOKER.

APPLICATION man 1M. 16. i915.

1N VEN TOR. Aem/w@ Jffmmm ff/ ww ATTORNEYS.

Fate/ated Aug. 8

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to all parts thereof and thereby permits thi food in the vessel 18 to become quickly and evenly heated. lVhcn the food is cold r large amount of heat is absorbed b v it, bu as it reaches the cooking tempe'ature a small amount ot' heat only is necessary 'to maintain it at such temperature. it is seen, there-tore, that variations in temperature in theV receptacle .Z are accompanied by variations in pressure, and means are provided ltor irai-ying the amount of heat supplied to the receptacle in proimrtion to the varia'- tions ot' ressm'e.therein.

The tiow of the heating fluid, which may be gas, hot air or other gases or steam, is controlled by means of a valve which is operated by variations in pressure within the receptacle. Arranged within the steam chan'iber or vacuumized chamber A,is a casing 2l in which is arranged a diaphragm 22, ont side oit' the diaphragm being exposed to tht pressure in the chamber. Engaging the other or lower side of the diaphragm is a plunger 23 which extends through the casing 21 into the valve casing 24, and .into Contact with the valve The lower end of the plunger is preferably rounded and seats in a cupped depression in the valve. The valve and the valve seat are tapered and the valve is provided with dependent guides 2G which are disposed in the gas passage 27, the guides being of such shape (Fie. that when the valve is unseated, the gas is free to pass through the passage.

Secured to the under side of the valve Q5 is a valve stem 28 which extends downward through the vertically adjustable nut 29, and surrounding the stem is a coiled spring 31 bearing at one end against the nut 2S) anc at the other end against the guides 2G. Tlu spring opposes the downward movement ot the diaphragm due to an increase in pressure within the chamber, and by varying the compression of the spring b v means of the nut 29 dii'ierent positions of the valve for a given pressure in the chamber may be obtained. Since in a closed receptacle containing steam the pressure varies with the temperature, the range'of temperature in the chamber may be varied by varying the compression of the spring. The diaphragm is preferably of the buckling type which is normally bowed downwardly, so that it exerts a pressureagain'st the spring, and wlreinthe pressure in the chamber is increased this pressure, in combination with the pressure exerted by the diaphragm, is opposed to the pressure of the spring.

Gas is admitted to the valve chamber below the valve 25 through the pipe 32 which extends through the shell 5 and is provided with a cock The burner 1.7 commnnicatcs with the valve casing above the valve through the conduit 34. A pilot or ignition burner 35 provided with a cock 36 connects to the valve casing helow the valvc when gas to be burned is used as the heating cle- 1nent,`the shell 5 is provided adjacent the bottom with a plurality ot' apertures i' tor admitting ai' and above the burner is prov vided with a plurality ot apertures 38 to permit the discharge of the products ot' combustion.

The operation ot the cooker is as follows: lVhen the cooker is cold the diaphragm in its upward position and the 'alve is unseated. as shown in Fig. rThe cock 33 is turned and the burners i7 and 35 lighted. The water in the chamber becomes heated and steanis, and the pressure within the vacuun'iized chamber increases, causing the diaphragm to move` downwardly, thereby lessening the supply oit gas to the burner 17, and consequently lessening the supply ot' heat to the receptacle. -When the burneil first ignited and the cooker is cold, the heat supply is at the maximum, and heat sup plied more rapidly than` it is imparted to the food, and as a consequence the temperature oft the chamber may become suliiciently high to increase the pressure therein to such a point that the valve. will be closed, in which case the pilot light ignites the gas when the valve is again opened. After the cooker has been in use for a short time, however, the `valve comes to a position of substantial rest at such a point that the amount at' heat supplied is just sutlicient to compensate for the heat consumed in. cooking the food and the heat lost.

I claim.

1. Acooker comprising a shell, a cookint4 receptacle comprising an annular closed chamber arranged within said shell and spaced apart therefrom, a metallic cylinder surrounding` said receptacle and supported within raid shell, a plate secured to the ower end o'l said cylinder and bearing against the bottom of said receptacle, and i means 'tor heating said receptacle.

2. cooker comprising a shell, an annular -)late having a depending liangc at its inner alge partly closing the' top of said shell, a cooking receptacle comprising an annular Slosed chamber arranged within the shell and secured at its upper edge to said flange, a metallic cylinder surrounding said receptacle secured at its upper edge to said flange, a plate secured to the lower edge ot' the cylinder and bearing against the bottom of said receptacle, a filling ot heat insulating material between said cylinder and shell, a cover arranged to tit inside ot said flange, and means tor heating said receptacle.

ln a cooker, a recel'itacle comprising an annular vacuninizcd chamber, a cylinder surrolnuling and spaced from said receptacle, a shell surrounding and spaced from said cylinder, a dmvnwardly turned flange on said shell to which said receptacle and ceptacle, a shell surrounding and spaed from said Wall, a flange on said shall for' supporting said' receptacle and wall, a filling of heat insulating material between said shell and said Wall and means for heating said receptacle.

In testimony whereof, I have hez'eunto set my hand at San Francisco7 California, this 8th day of January, 1915.

ARTHUR J. In presence nf- I-I. G. PROST, J. B. GARDNER. 

